This invention relates to a system for controlling torque through a planetary gear system. More specifically, the invention relates to the use of an oil pump with a fast acting integral valve to control torque, particularly wheel torque, in an automobile.
In all-wheel drive or four-wheel drive automobiles, one set of wheels is directly connected to the power source through a transmission, an axle, and a series of shafts. The other set of wheels can be connected to the power source through a center differential, a coupling, or an active clutch. Typically, the function of the center differential is to regulate the proportion of power that is transmitted between the front and rear sets of wheels, thereby controlling vehicle traction and cornering characteristics.
Brakes, motors, and electric generators have been combined with planetary and differential systems to control wheel torque in automobiles. Many current systems regulate torque transfer between the front and rear sets of wheels by controlling the drag between plates in a fluid-filled clutch. The use of a clutch to transfer torque is expensive to implement, however, and the operation of the clutch generates a high amount of friction that dissipates a substantial amount of the torque being transferred. A more efficient and less expensive system to transfer torque is therefore desired.
The below-described system of a pump combined with a planetary gear system transfers torque efficiently and controllably. The pump comprises an inner rotor, an outer rotor, an inlet port and an outlet port for a fluid, and a bore located between the inlet port and the outlet port. A valve, which is physically attached to a valve drive device, controls the flow of fluid within the bore. The valve drive device, along with a controller, positions the valve within the bore. When the valve is positioned to block the flow of fluid between the inlet and outlet ports of the pump, pressure is generated within the pump. The pressure of the pump generates torque in the planetary gear system.
Another embodiment of this invention is a method of regulating torque in a planetary gear system. First, the position of a valve for a pump is controlled. Pressure is then generated within the pump, and the torque generated is transferred to a planetary gear system by a sun gear attached to the pump.
Other systems, methods, features, and advantages of the invention will become apparent to one skilled in the art upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are intended to be included within the scope of the invention, and protected by the accompanying claims.